Conventionally, as a method for decorating the surface of a resin molded article, there has been a method of transfer simultaneous with molding. The method of transfer simultaneous with molding is a method for providing decoration by placing, in a metal mold, a transfer member having transfer layers including a release layer, a patterned layer, an adhesive layer, and so on are laminated in order on a substrate sheet injecting and stuffing a resin into a cavity, making the transfer member adhere to a surface of a resin molded article simultaneously with obtaining the resin molded article by cooling, and thereafter peeling off the substrate sheet and transferring the transfer layers onto the surface of the resin molded article.
In general, the transfer member used for the method of transfer simultaneous with molding is formed by printing the layers on an elongated substrate sheet in accordance with the width of the roll of a printing machine and used by being cut (slit) into an appropriate width in accordance with the size of an object to receive transfer (object to which transfer layers of the transfer member are to be transferred), and thereafter transferred.
In this case, there has been a drawback of the occurrence of a foil flaking phenomenon in which ink film flakes 131 constituted of a peel layer 104, an anchor layer 107, a patterned layer 105, an adhesive layer 106, and so on peel off the surface of a mold release layer 103 formed on the substrate sheet 102 at the slit portion of the transfer member which is caused by an impact occurring when the blade 130 hits at the time of slitting as shown in FIGS. 12 and 13. This is because not only the portion subjected to transfer but also the portion that is not subjected to transfer have excellent peelability between the substrate sheet and the transfer layers of the transfer member. The foil flaking has occurred more significantly as the thickness of the transfer layers is increased as in the case where there are many patterned layers as transfer layers, in the case where a vapor deposition layer is required to be provided as a patterned layer, in the case where the peel layer cannot help being thick as in the case of a hard coat transfer member, in the case where there is many function layers, and in similar cases.
As a result, it has occasionally been the case where the ink film flakes have adhered again to the transfer member and entered between the object and the transfer layers during transfer. Furthermore, carrying out the transfer simultaneous with molding with an ink film flake adhered to the back surface of the transfer member has caused the adhesion of the ink film flakes to the cavity surfaces of the metal mold, occasionally causing a dint (called a dent) due to the ink film flake on the surface of the molded article.
Accordingly, there is a transfer member in which the mold release layer 103 is provided in a belt-like pattern excluding a portion to be brought in contact with a slit portion 108 when the mold release layer 103 is provided on a substrate sheet, and in which transfer layers including a peel layer 109, a patterned layer 105, an adhesive layer 106, and so on are provided on the mold release layer 103 in order to prevent the occurrence of foil flaking during slitting (refer to FIG. 4 and Unexamined Japanese Patent Publication No. 11-58584).
Moreover, it can be considered to provide all the transfer layers in a pattern instead of providing the mold release layer 103 all over the surface and constitute the transfer member 101 so that the slit blade does not come in contact with the transfer layers during slitting (see FIG. 5).
However, there has been an issue that, when a metal mold 111 having a side gate 113 is used in the case where the transfer simultaneous with molding is carried out by using the transfer member 101 of the construction shown in FIG. 4, a runner portion 113a for the molding resin communicating with a cavity 112 as shown in FIG. 10 is brought in contact with the neighborhood of the slit portion 108 of the transfer member 101 (Note that in FIG. 10, reference numeral 80 denotes a region where the mold release layer 103 is provided, and 81 denotes a region where the mold release layer 103 is not provided), and the sprue runner for the molding resin fuses to the adhesive layer 106 of the transfer member 101 (as shown in FIG. 11, in an injection molding state, a portion for peeling-off is only a portion 84 which is an interface of the mold release layer 103 and the peel layer 104 for peeling-off after transfer, and peeling-off can not be performed at the other portion, and there is provided the adhesive layer 106 on the sprue runner side of the molding resin portion 120, there is no peel portion on this side, and thus the sprue runner for the molding resin fuses to the adhesive layer 106), failing in carrying out continuous molding as a consequence of the break of the transfer member 101 or other trouble (see FIG. 6). Particularly when carrying out the transfer simultaneous with molding on both sides of the molded article by using two transfer members 101 as shown in FIG. 10, the molding resin flows in contact with the edge portion of either transfer member 101, and therefore, the aforementioned phenomenon occurs more easily.
Moreover, in the transfer member of the construction shown in FIG. 5, an ionizing radiation curing resin is used as the peel layer 109 when the surface strength of the transfer molded article is desired to be improved. However, the thickness of the ionizing radiation curing resin has been limited when formed by being partially patterned by a printing method, and this therefore has led to an issue that a sufficient surface strength has not been able to be obtained.
Accordingly, the object of the present invention is to solve the aforementioned issues and provide a transfer member capable of being continuously formed by a method of transfer simultaneous with molding and obtaining a molded article having excellent surface strength.